Bananas are among the highest fruit sources of protein with 1.22 grams of protein per cup. Blackberries have 1 gram of protein per cup, and apples, blueberries, cherries, grapefruit and apricots have lesser amounts.
Fruits are generally poor sources of protein, but other plant-based foods such as whole grains and legumes provide more. Soybeans are especially rich in protein with 29 grams per cup when cooked. Other good protein sources include soy products, nuts, seeds and nut butters. Many vegetables contain modest amounts of protein, including corn, artichokes, asparagus, broccoli and spinach.
Plant-based diets that exclude all animal foods are typically lower in protein than the average American diet but can still meet the recommended daily allowance of 0.36 grams of protein per pound of body weight without undue difficulty. The key is consumption of a wide variety of foods to ensure both adequate protein intake and getting enough of all nine essential amino acids. Because vitamin B-12, vitamin D, omega-3 fatty acids, iron and zinc are either largely absent from plant sources or not as easily absorbed from plant than animal sources, people eating vegan diets need to exercise care in planning their diets to meet these needs and may need supplements in some cases.